By now we all know it. A component’s power cord is not the end of the lengthy road your utility power traveled from your power station to your digs. From the component’s perspective it's where it all begins. It's the first few feet of power pathway it sees. With a relative high number of components sitting close to each other in the hifi rack, there are a number of such starting points packed tightly together. One would think that shielding of power cords is vital to avoid RF and EMI interference for the nearby components. Whilst such shielding is mandatory for transmission lines that carry low-level audio signals like interconnects, power cords follow other rules.

With power cables shielding creates higher capacitance which leads to a less dynamic character of the music. To keep capacitance low despite a shield, the shield should be well spaced away from the conductors. This necessitates a thick inflexible construction. In an AC-powered system, impedance is very low to reduce susceptibility to RF/EMI. For power cords. Again, interconnects are different. To shield a power cord properly a manufacturer must spend serious money which in the end is funded by the consumer whilst the outcome is questionable in its effectiveness. In fact the sonic effects of a shielded power cable are mostly various forms of tuning.